1. Field of the Invention
This invention relates to a semiconductor device for clocking a CMOS (complementary metal-oxide semiconductor) or other device.
2. Background Art
Recently, there has been an accelerating demand for enhancing the speed of LSI (large scale integrated circuit) and reducing its power consumption. With regard to speed enhancement, electric interconnection delay is becoming a crucial factor hindering the speed enhancement of LSI. This has triggered growing needs for optically driving a circuit, and activated research and development of on-chip optical interconnection and optoelectric hybrid LSI based thereon.
Core elements in an optoelectric hybrid LSI include a light emitting element for outputting an optical signal, an optical waveguide for transmitting an optical signal, and a light receiving element for receiving an optical signal. The circuit function differs depending on whether the light emitting element and the light receiving element reside inside or outside the LSI chip.
More specifically, an optoelectric hybrid LSI needs to include a light receiving element within the chip, thereby enabling optical clocking. Further providing a light emitting element within the chip also enables optical input/output and optical computation, which are conventionally believed difficult to realize.
Providing a light receiving element within the chip enables fast optical clocking. However, if the optoelectric conversion in optical clocking is based on current conversion, there is a problem of very high power consumption.
In this respect, JP-A 6-209119(Kokai) discloses a semiconductor device based on voltage conversion of light. More specifically, in the semiconductor device disclosed in JP-A 6-209119(Kokai), a photodiode is connected to the gate of a CMOS, and the channel of the CMOS is turned on by optically generated carriers.
However, the semiconductor device disclosed in JP-A 6-209119(Kokai) has no mechanism for eliminating optical carriers accumulated in the gate of the CMOS, and hence it cannot be turned off.